1. Field of the Invention
This invention relates to an automatic light adjustment device which carries out light adjustment in accordance with the results of a divisional photometry performed, at the time of flashing, on a field divided into a plurality of divisional areas.
2. Related Background Art
The present applicant proposed a TTL automatic light adjustment camera in the specification of U.S. patent Ser. No. 672,055; it is a camera capable of making a preliminary and a main flash and adapted to perform divisional photometry on a field divided into a plurality of photometric areas, at the time of preliminary flashing. Of the plurality of photometric areas, the ones whose photometry outputs (the levels of the corresponding photometric signals) are not within a fixed range (i.e., either above or below this fixed range) are regarded as areas on which light adjustment should not be performed and are excluded with respect to the light adjustment which is performed at the time of main flashing. This is, the instant at which the main flashing is to be stopped is determined exclusively on the basis of the photometric signals of those areas whose photometry outputs at the time of preliminary flashing are within a predetermined range (a light adjustment range). This arrangement provides the following advantage: If, for example, there exists in the field an object of high reflectance, such as a gold-leafed folding screen, or, if the background of the principal subject is missing, light adjustment is performed without taking into account the photometric signals of those areas corresponding to such an object or the missing background, with the result that the subject is more likely to be photographed with correct exposure.
The camera described above, however, is not able to adequately cope with a situation where all the photometric areas are to be excluded with respect to light adjustment; it is possible, in such a case, that correct exposure cannot be obtained. Further, even when it is only part of the photometric areas that is to be excluded, it may be difficult, in some cases, to obtain correct exposure solely by excluding such areas with respect to the light adjustment at the time of main flashing.
Another problem to be considered is that there are cases where object distance detection cannot be performed. This will happen, for example, when the AF (automatic focusing) adopted is of an in-lens-motor type and the photographic lens used is equipped with no distance encoder, or, even with an automatic focusing of an in-body-motor type, when the camera is used on a manual-focusing basis, or else, when a conventional photographic lens for MF (manual focusing) is used. In such cases, reflectance calculation cannot be performed, so that the extraction of any areas to be excluded (cut areas) is impossible or can only be effected inaccurately.